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The present study investigates the effect on methane production from waste paper when co-digested with macroalgal biomass. Both feedstocks were previously mechanically pretreated to reduce their particle size. The study was planned according two factors: the feedstock to inoculum (F/I) ratio and the waste paper to macroalgae (WP/MA) ratio. The F/I ratios checked were 0.2, 0.3 and 0.4 and the WP/MA ratios were 0:100, 25:75, 50:50, 75:25 and 100:0. The highest methane yield (386 L kg −1 VS added ) was achieved at an F/I ratio of 0.2 and a WP/MA ratio of 50:50. A biodegradability index of 0.87 obtained in this study indicates complete conversion of feedstock at an optimum C/N ratio of 26. Synergistic effect was found for WP/MA 25:75, 50:50 and 75:25 mixing ratios compared with the substrates mono-digestion. [ABSTRACT FROM AUTHOR]

[Display omitted] • A total of 20 different paper sludges were investigated. • A wide range of biomethane potentials was determined. • Inhibiting substances for some paper sludge were identified. • Co-digestion resulted in methane yield increase of 5–10%. • The possibility of anaerobic co-digestion could be demonstrated. In this work, the feasibility of the anaerobic digestion of paper sludge as a co-substrate in anaerobic digestion mechanical–biological treatment (MBT) plants is investigated. In the first phase, the biochemical properties, biomethane potential (BMP), and pollutant contents of 20 different industrial paper sludges are determined. Following the general evaluation in the BMP tests, the second phase of the project involves the semi-continuous co-digestion of six paper sludges in continuous stirred reactors (CSTR). Paper sludges are categorized according to their origin within the pulp and paper mills: Deinking Sludge (DS), Primary Sludge (PS) and Biological Sludge (BS). The analysis of potentially inhibiting elements shows that the concentrations of chlororganic compounds, mineral oil and some heavy metals are highest in DS, while the mean heavy metal loads in all paper sludges are relatively low compared to other industrial sludges. Large differences in total solids (TS) and volatile solids (VS) contents are observed among the different paper sludges investigated, with DS having the highest TS due to the high inorganic contents. The BMP of the investigated sludges ranges from 90 to 355 NL CH 4 kg−1 VS. In subsequent semi-continuous co-digestion experiments simulating MBT conditions, three DS and two fiber sludges (a mixture of PS and BS) show good methane generation rates, while one fiber sludge causes inhibition and indicates an increase in viscosity. In general, co-digestion of paper sludge in anaerobic digestion MBT plants can be a viable option for energy production and also facilitates a safe disposal of the paper sludge digestates. [ABSTRACT FROM AUTHOR]

In the anaerobic digestion of lignocellulosic materials such as waste paper, the accessibility of microorganisms to the fermentable sugars is restricted by their complex structure. A mechanical pretreatment with a Hollander beater was assessed in order to reduce the biomass particle size and to increase the feedstock’ specific surface area available to the microorganisms, and therefore improve the biogas yield. Pretreatment of paper waste for 60 min improves the methane yield by 21%, from a value of 210 ml/gVS corresponding to untreated paper waste to 254 ml/gVS. 30 min pretreatment have no significant effect on the methane yield. A response surface methodology was used to evaluate the effect of the beating time and feedstock/inoculum ratio on the methane yield. An optimum methane yield of 253 ml/gVS was achieved at 55 min of beating pretreatment and a F/I ratio of 0.3. [ABSTRACT FROM AUTHOR]

Abstract: In Lao PDR, a least developed country in South-East Asia, provision of electricity to remote areas is a high priority for the Government, which has the objective of electrifying 90% of the population (in terms of number of households) by the year 2020. While this objective is commendable and tremendous progress has been made over the past 10 years in terms of rural electrification, some important questions remain unanswered. Currently, grid extension is the main technical option considered. One of the main reasons for this push for grid extension is the assumption that access to the grid means development. However, when analysed closely, the reality from the field is far more complex. Although grid electricity has tremendous potential to provide economic development opportunities in rural areas, it also has some drawbacks. In particular, productive activities fail to develop in many grid connected villages where the demand for electricity remains low even after a few years after having been grid electrified. This paper argues that alternative options to grid extension, e.g. off-grid decentralised renewable energy (DRE), exist, are often more attractive financially and could be promoted more effectively. These technologies can be cheaper than grid extension, even on a like-for-like comparison. 2 [2] Comparing the cost of each option supplying the same amount of electricity (in kWh). DRE technologies also provide opportunities for development, even without driving large productive loads. These opportunities are presented in terms of 1) the flexibility of needs that DRE technologies can satisfy, 2) empowerment of rural communities and 3) decentralised decision making processes. So far, the promotion of DRE in Laos has not always been successful, but this should not be an argument against promoting these options. A close look at recent rural electrification project budgets reveals indeed that grid extension is far more subsidised than DRE, raising concerns about the social equity of such projects. [Copyright &y& Elsevier]

Ample interest for more efficient utilization of bio-based residues has emerged in the Nordic pulp and paper (P&P) industry, which uses virgin wood as feedstock. Although different bioenergy retrofit technologies for production of liquid, solid, and gaseous bioenergy products have been applied in the existing P&P mills, the number of installations remains small. The lack of profound knowledge of existing bioenergy retrofits hinders the replication and market uptake of potential technologies. This review synthesises the existing knowledge of European installations and identifies the key drivers and barriers for implementation to foster the market uptake of potential technologies. The bioenergy retrofits were reviewed in terms of technical maturity, drivers, barriers and market potential. Based on this evaluation, common drivers and barriers towards wider market uptake were outlined from political, economic, social, technical, environmental, and legal perspective. Technologies already commercially applied include anaerobic fermentation of sludge, bark gasification, tall oil diesel and bioethanol production, whereas lignin extraction, biomethanol production, hydrothermal liquefaction and hydrothermal carbonization are being demonstrated or first applications are under construction. The findings of this review show that a stable flow of residues at P&P mills creates a solid base for retrofitting. New innovative bio-based products would allow widening the companies' product portfolios and creating new businesses. Also, European Union's (EU) legislation drives towards advanced biofuels production. Wider uptake of the retrofitting technologies requires overcoming the barriers related to uncertainty of economic feasibility and unestablished markets for new products rather than technical immaturity. • Bioenergy retrofits can widen the product portfolio of the pulp and paper industry. • Bioenergy retrofits in Europe were comprehensively reviewed for the first time. • Drivers and barriers for the market uptake were assessed from different perspectives. • Retrofits support the REDII targets for advanced biofuels in transport sector. • Utilization of residues for bioenergy products improves mills' resource efficiency. [ABSTRACT FROM AUTHOR]

Pulp and paper industry is a water-intensive industry. This industry commonly produces considerable amount of effluent, especially from virgin raw materials processing. The effluent, namely pulp and paper mill effluent has the potential to adversely affect the receiving watercourses. However, the nutrients in the pulp and paper mill effluent could be reused as a substrate in biohydrogen production. In this study, photofermentative biohydrogen production was investigated using Rhodobacter sphaeroides and pulp and paper mill effluent as a substrate. An application of low power ultrasound on R. sphaeroides was predicted to increase photofermentative biohydrogen production but excessive ultrasound effects might inhibit the production due to possible cell disruption. Hence, various ultrasonication duration (5, 10 and 15 min) and amplitude (15%, 30% and 45%) were applied on the bacteria to determine the recommended ultrasonication conditions for improving biohydrogen production. The recommended conditions were operated at ultrasonication amplitude and duration of 30% and 10 min, respectively. A maximum biohydrogen yield of 9.62 mL bioH 2 /mL medium was obtained under this condition, which was 66.7% higher than the result obtained using R. sphaeroides without undergoing ultrasonication (control). The light efficiency and cell concentration were increased by 67% and 150%, respectively, using ultrasonication amplitude and duration of 30% and 10 min, respectively as compared to the control. The present results demonstrated that moderate power of ultrasonication applied on R. sphaeroides was an effective method for enhancing photofermentative biohydrogen production using raw pulp and paper mill effluent as a bioresource. [ABSTRACT FROM AUTHOR]

Pulp and paper industry is one of the most polluting, energy and water intensive industries in the world. Produced pulp and paper mill sludge (PPMS) faces a major problem for handling and its management. An anaerobic digestion has become an alternative source. This review provides a detailed summary of anaerobic digestion of PPMS – An overview of the developments and improvement opportunities. This paper explores the different pretreatment methods to enhance biogas production from the PPMS. First, the paper gives an overview of PPMS production, and then it reviews PPMS as a substrate for anaerobic digestion with or without pretreatment. Finally, it discuss the optimal condition and concentration of organic and inorganic compounds required for the anaerobic metabolic activity. Future research should focus on the combination of different pretreatment technologies, relationship between sludge composition, reactor design and its operation, and microbial community dynamics. [ABSTRACT FROM AUTHOR]

This work reports an innovative simulation method for effectively utilizing paper-mill sludge based on the co-gasification approach for energy-enriched renewable fuel production. An Aspen plus-based co-gasification model was developed to simulate and examine the synergetic effects of biomass and paper-mill sludge co-gasification. Initially, the model was validated using experimental data from the reported literature and found good agreement regarding gasification and co-gasification approaches. Sensitivity analysis of biomass gasification revealed that the maximum H 2 content of 29.6% and CO (36.0%), LHV (7.8 MJ/Nm3), 72.2% (CCE) was obtained at optimal (850 °C: temperature; 1 bar: pressure; 0.2: ER) conditions. Further, the H 2 proportion enhanced, and CO declined to 38.8 and 30.7% at the same operating conditions, respectively, with a co-gasification ratio of 50% compared to 0% (H 2 : 29.6% and CO: 36.0%). However, with increasing the co-gasification ratio beyond 20%, the CO content started to follow upward trends; at the same CGR, the H 2 , LHV, and CCE observed were 36.0%, 7.76 MJ/Nm3, and 65.2%, respectively. Hence, the developed co-gasification model can provide vital information for large-scale gasifier design, operating decisions, and optimization using different biomass blends. • Biomass and PMS utilization to produce renewable fuel. • Co-gasification parametric effects evaluation on product yield. • Increasing the proportion of PMS in feedstock mixture increases H 2 content. • 20% PMS co-gasification provided consistency with reported literature. [ABSTRACT FROM AUTHOR]

The paper is devoted to the development of a device for protecting facilities with turn-to-turn insulation, namely transformers and wind generators in order to increase the reliability of operation of electrical power systems, renewable energy installations and energy storage systems. The paper presents the results of experimental studies of the parameters of a prototype frequency-dependent device, as well as an assessment of the effectiveness of suppression of high-frequency surge voltages by the proposed device. The results of four groups of measurements are shown, which were compared with each other and with the results of previously showed computer simulations. The high efficiency of the proposed device when influencing the slope and amplitude of short high-frequency transients is shown. It is indicated that the parameters proposed earlier in the simulation allow the device to be used effectively. A brief analysis of alternative methods and means of protection is provided, and the prospects for using the device as protective equipment for wind power plants are also considered. [ABSTRACT FROM AUTHOR]

Green hydrogen is crucial for society's access to peaceful, secure, and stable energy sources to flourish sustainably and get universal government support. To protect the environment and provide energy security, it is essential to use hydrogen as a sustainable fuel and energy source to cover the energy baseload. This paper investigates the developments of renewable energy (RE) and the potential for green hydrogen in the Middle East and North Africa (MENA) region. There is a considerable chance to use RE because of the MENA region's excellent solar radiation. On the other hand, many countries in the MENA region are classified as one of the poorest in water resources and are known to have water-energy challenges. This paper focuses on the water needed to produce hydrogen in countries with water scarcity. A strengths, weaknesses, opportunities, and threats (SWOT) analysis was performed for green hydrogen generation in the MENA, where recommendations for countries with a water-energy nexus can be made. Additionally, this paper offers suggestions for creating a sustainable hydrogen economy, such as cutting back on the domestic use of fossil fuels, subsidizing the renewable production industry, and supporting hydrogen manufacturing. • Green hydrogen production is highly affected by water scarcity. • SWOT analysis was performed on green hydrogen generation in the MENA. • Recommendations were provided on a country-by-country basis. [ABSTRACT FROM AUTHOR]

This paper investigates the impacts of economic (in)stability on carbon emissions and the role of renewable energy in these effects at the crossroads of accelerated climate change and rising global economic instability. The paper hypothesizes that these implications should be examined not by direct impacts across variables, but rather via indirect effects serially mediated by renewable energy consumption and economic growth. This paper analyzes the United States from January 1980 and April 2022 using manifest structural equation modeling. The paper reaches two major conclusions. First, there are clear distinctions between (i) the direct and indirect effects of economic stability, surrogated by inflation and policy interest rate, on carbon emissions, (ii) the symmetric and asymmetric indirect effects, and (iii) the roles of aggregate renewable energy and its components, such as biomass and hydropower energy use, in mediating these symmetric and asymmetric indirect effects. Second, renewable energy significantly reduces the carbon-increasing effects of inflation and interest rates. The paper contains proper policy suggestions based on the findings. [ABSTRACT FROM AUTHOR]

The global problem of climate change and difficulties related to energy access, air pollution, and water pollution in India (and other developing countries) necessitate the need to look for alternative clean, local, and low-carbon energy sources for displacing fossil fuels. This paper analyses the existing waste-to-biomethane potential of the sericulture, fisheries, and agro-industrial sectors in India, which have mostly been neglected previously in India's waste-to-energy assessments. In the process, the volume of wastewaters generated from India's agro-industries are also estimated, data on which are scarce in the academic and grey literature. India's annual biomethane potentials (for 2018–19) were found to be 88 million m3, 207 million m3, and 3514 million m3 from the three sectors, respectively. To assess the energy generation potential of these wastes, a comprehensive literature review was conducted and data on residue-to-product ratios, results of proximate analyses, and specific biomethane yields were either compiled or calculated. The gross thermal energy and electricity generation potentials are 132 PJ and 22 TWh respectively; between 19 and 95 million people can benefit from such waste-to-energy production, depending on the end use of the biomethane for electricity generation or as a domestic cooking fuel. The corresponding mean removal of organic pollution from India's surface waters can be between 5.5 and 9.3 million tonnes of chemical oxygen demand. For the end uses of biomethane in electricity generation and cooking, the cumulative GHG abatements attributable to these industries are 11.4 million tonnes and 6.8 million tonnes of carbon dioxide-equivalent respectively. Besides the numeric results reported, this paper also contains a comprehensive compilation of data on waste characteristics and biomethane productions. The present status of biogas generation and related policy implementation in India are reviewed and discussed. Overall, our findings indicate that biomethane from these wastes and wastewaters can generate substantial energy for India, is in line with recent government policies, and can aid India in achieving six Sustainable Development Goals of the United Nations. • Annual estimates of wastes from India's sericulture, fisheries and agro-industries • The corresponding annual biomethane generation potential is 3810 million m3. • Clean electricity or cooking gas for 19 and 95 million people respectively • Quantitative estimates of atmospheric GHG and surface water COD removals • Biomethane data compilation and a review of present status and policies in India [ABSTRACT FROM AUTHOR]

Attributed to the growing focus on energy savings and eco-friendliness, the solar PV-based DC Nano-grids for residential and commercial buildings are becoming more popular. On the other hand, solar photovoltaic systems (SPV) are intermittent and unreliable due to their dependency on external factors such as solar irradiance, ambient temperature, and unpredictable shadows. In addition, the power degradation occurs in SPV systems due to module mismatch losses caused by various factors like partial shading (PS), dissimilar aging effect, different power ratings, etc. The conventional PV system cannot handle all these issues, so it is essential to address them. This paper proposes a bidirectional modular PV battery system (BMPBS) that uses non-isolated buck and boost converter combinations. This system is capable of self-sustained generation, storage, and bidirectional power flow within the Nano-grid. The proposed BMPBS can handle losses due to module mismatch and intermittency in SPV with the help of battery storage system (BSS), making the overall SPV system reliable. It requires single-stage power conversion to extract maximum power from each PV module and BSS charging and discharging. Its modular design allows it to function across various voltage, power, and BSS choices. This paper discusses the operation, steady-state analysis, and dynamic analysis of the proposed BMPBS. The performance of the proposed BMPBS is validated using a state-of-the-art experimental setup with two PV modules, each having a rating of 90 W P . • The proposed BMPBS is capable of self-sustained generation, storage, and bidirectional power flow within the Nano-grid. • The proposed BMPBS can handle open circuit in SPV or battery module. • The proposed BMPBS can mitigate the module mismatch losses of solar PV (SPV). • The proposed BMPBS is able to handle intermittency in SPV with the help of a battery storage system (BSS). • This system requires single stage power conversion increasing the overall efficiency. • This system uses single inductor making the overall system compact. • Its modular design allows it to function across various voltage, power, and BSS choices. [ABSTRACT FROM AUTHOR]

Vanadium Flow Batteries (VFBs) are a stationary energy storage technology, that can play a pivotal role in the integration of renewable sources into the electrical grid, thanks to unique advantages like power and energy independent sizing, no risk of explosion or fire and extremely long operating life. The first part of this paper presents the main features and the basic performance parameters of VFB, which determine their electric, hydraulic, thermal, and aging feature. The latter part outlines the strengths and weaknesses of the technology, the services that it can provide to the grid, and a short economic analysis. After presenting the fundaments of the technology, prospects and trends of VFBs deployment are outlined. Most of the considerations highlighted in this paper are inspired to studies performed on an industrial-size VFB operated at the Electrochemical Energy Storage and Conversion Lab (EESCoLab) at the University of Padua (Italy). [ABSTRACT FROM AUTHOR]

Along with the popularity of the environment, social and governance (ESG) concerns, the circular economy concept has gained tremendous attraction from the industries, policy makers and academicians. On a firm level, this is implemented through the so-called Circular Business Model (CBM), which is seen through various initiatives. This includes firms in the energy industry, who are transitioning from conventional to renewable energy sources. Nevertheless, despite of the importance and the omnipresence of the practice, there is still lack of empirical research within the CBM topic. In particular, empirical research combining the CBM and technological innovation topic within energy industry (as technology-intensive and high risk industry) in developing country such as Indonesia, is still lacking. To answer this gap, using literature review as research method, this paper has arrived into the following propositions as main result; (1) there is a positive relationship between firm's level of CBM and technology innovation adoption to firm's performance, where (2) the two antecedents that are positively impacting firm's level of CBM and technology innovation adoption are leader's innovativeness and perceived level of technology. For academicians, this research is expected to provide contribution to the energy transition literatures within CBM and technology innovation adoption topic. Propositions provided in this paper is expected to serve as valuable basis in conducting further empirical research. For practitioners, this research is expected to provide valuable insights to make improvements and/or innovations in terms of business model, technology adoption, and strategy. At last, this research is expected to support energy transition. [ABSTRACT FROM AUTHOR]

[Display omitted] • The load capacity curve hypothesis for green energy and ecological footprints. • Employ GMM and Panel quantile regression for 2000–2020. • Greener energy consumption (GEC) determines load capacity factor (LCP) unlike to ecological footprint and bio-capacity. • Renewable and Clean energy is recommended to address climatic vulnerability. • Study discusses policy-related implications for sustainable development. This paper examines the load capacity curve hypothesis by the tourism and renewable energy from top tourism economies in the World. We employ the data from 2000 to 2020 and applied the panel GMM and panel quantile regression to arrive at our empirical findings. The results of the two models demonstrate the non-validity of the Load Capability Curve (LCC) hypothesis and the significant role of touristic arrival (TRA) and greener energy consumption (GEC) on the load capacity factor (LCP) by contrasting the ecological footprint per capita and bio-capacity. Furthermore, renewable and clean energy is recommended to address air pollution and climatic vulnerability. Thus, the empirical results of the current study provide acumens for policymakers of top tourism economies to consume green innovation technologies to counterbalance the environmental and socio-economic issues induced by the tourism sector without halting economic growth and sustainable tourism development. The study discusses policy-related implications for sustainable development. [ABSTRACT FROM AUTHOR]

[Display omitted] • The determinants of the load capacity factor are investigated in top SDGs nations. • Distributional heterogeneity controlled using novel Method of Moments Quantile Regression. • Technology, renewable energy, globalization and environmental tax increase the load capacity factor. • Economic growth curb load capacity factor. • Interaction between renewable energy and technology innovation reduces load capacity factor level. The acceptance of Sustainable Development Goals (SDGs) in 2015 shifted the consideration toward sustainability-linked aspects in both developed and developing nations. Currently, the most critical ecological and economic problems are associated to ecological contamination and sustainability. Thus, this current study employs load capacity factor (LCF), a comprehensive ecological assessment tool that captures both the ecological foot (demand side) and biocapacity (supply side) of the ecosystem to scrutinize the effect of environmental taxes, technological innovation and renewable energy on LCF while regulatory for globalization and economic progress in the case of top ten SDGs nations. The paper used MMQR to capture the influence of each variable at different quantiles from 1994 to 2018. The study's outcome shows that technology innovation, environmental Tax, renewable energy and globalization are negative and significant in reducing LCF within the countries. Again, the study exposed that economic growth contributes positively to LCF. However, the interaction term between technology innovation and renewable energy upsurges the LCF across all the quantiles. Moreover, the panel Dumitrescu and Hurlin causality test results revealed a one-way causality exists between economic growth and LCF, running from economic growth to LCF. The outcomes of this research will have a significant impact on the route that policymakers in these nations take in reaching net zero emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Environmental impact modeling under EKC and LCC hypotheses examined. • LM-Bootstrap Cointegration tests and Drisscoll-Kraay regressions applied. • Financial development and load capacity factor are negatively correlated. • Environmental quality is adversely affected by economic expansion. • EKC and LCC hypotheses are valid for BRICS countries. Multiple human activities influence the physical environment, interacting with humans and their surroundings. Our existence depends on various natural resources harvested or extracted from the environment, such as food, materials, and energy. This paper examines the environmental impact modeling and efficient use of nuclear and renewable energy while considering the roles of energy efficiency under the assumptions of EKC and LCC hypotheses in BRICS countries from 1990 to 2018. The long-run estimates are based on LM-Bootstrap Cointegration tests and Drisscoll-Kraay regressions. Financial development has been observed to have a negative relationship with the load capacity factor. However, interestingly, financial development has been found to have a positive relationship with CO 2 emissions. Our findings indicate that the load capacity factor negatively correlates with economic growth in the long run—an increase in economic growth results in a reduction in load capacity. The long-term impact of economic expansion is a decline in environmental quality. Moreover, economic growth square is positive in the load capacity factor and negative in the case of CO 2 emissions. This situation reflects the EKC and LCC hypothesis in the BRICS countries. When income increases, environmental quality initially decreases, and once a certain level of income is reached, ecological sensitivity and green technologies increase the load capacity factor. The negative coefficient value in the case of economic growth and the positive coefficient value of the square root of economic growth determines the LCC hypothesis, which is U shape relationship. On the other hand, the negative coefficient value of economic growth followed by the positive coefficient value of the square root of economic growth determines the existence of the EKC hypothesis in the BRICS countries, which is an inverse relationship. Research limitations and future directions are discussed. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carriers (LOHC) can be used as a lossless form of hydrogen storage at ambient conditions. The storage cycle consists of the exothermic hydrogenation of a hydrogen-lean molecule at the start of the transport, usually the hydrogen production site, becoming a hydrogen-rich molecule. This loaded molecule can be transported long distances or be used as long-term storage due to its ability to not lose hydrogen over long periods of time. At the site or time of required hydrogen production, the hydrogen can be released through an endothermic dehydrogenation reaction. LOHCs show similar properties to crude oils, such as petroleum and diesel, allowing easy handling and possibilities of integration with current infrastructure. Using this background, this paper reviews a variety of aspects of the LOHC life cycle, with a focus on currently studied materials. Important factors such as the hydrogenation and dehydrogenation requirements for each material are analysed to determine their ability to be used in current scenarios. Toluene and dibenzyltoluene are attractive options with promising storage attributes, however their dehydrogenation enthalpies remain a problem. The economic feasibility of LOHCs being used as a delivery device were briefly analysed. LOHCs have been shown to be the cheapest option for long distance transport (>200 km), and are cheaper than most at shorter distances in terms of specifically transport costs. The major capital cost of an LOHC delivery chain remains the initial investment for the raw materials and the cost of equipment for performing hydrogenation and dehydrogenation. Finally, some studies in developing the LOHC field were discussed, such as microwave enhancing parts of the process and mixing LOHCs to acquire more advantageous properties. • Efficient hydrogen storage solution for sustainable energy transportation and storage. • Enables safe and cost-effective hydrogen transportation and distribution networks. • Promotes renewable energy integration through versatile and scalable storage capabilities. • Facilitates decarbonization efforts by enabling long-term, stable hydrogen supply chains. [ABSTRACT FROM AUTHOR]

A range of existing and newly developed hydrogen standards, certification and labelling (SCL) schemes aim to promote the role of 'renewable', 'clean' or 'green' hydrogen in decarbonising energy transitions. This paper analyses a sample of these SCLs to assess their role in the scaling up of renewable hydrogen and its derivatives. To analyse these hydrogen SCLs, we embellish a novel conceptual framework that brings together Sustainability, Systems Thinking, and Governance (SSG) literatures. The results reveal noteworthy scheme differences in motivation, approach, criteria, and governance; highlighting the complex, interconnected, and dynamic reality within which energy systems are embedded. We consider whether the sustainable utilisation of renewable hydrogen is well-served by the proliferation of SCLs and recommend an SSG-informed approach. An SSG approach will better promote collaboration towards an authoritative, global, multistakeholder, compromise on hydrogen certification that balances economic considerations with social, and environmental dimensions. [Display omitted] • There is a proliferation of hydrogen standards, certification and labelling (SCL) schemes. • We analyse a sample of SCLs to investigate their role in scaling green hydrogen. • We employ a Sustainability, Systems Thinking, and Governance (SSG) approach. • We recommend an SSG lens to help craft a global multistakeholder initiative. [ABSTRACT FROM AUTHOR]

This article presents a state-of-the-art review of the status, development, and prospects of DC-based microgrids. In recent years, researchers' focus has shifted to DC-based microgrids as a better and more feasible solution for meeting local loads at the consumer level while complementing a given power system's reliability, stability, and controllability. DC microgrid has an advantage in terms of compatibility with renewable energy systems (RESs), energy storage, modern electrical appliances, high efficiency, and reliability. However, the integration of different distributed generations has complicated the control of bus voltage and current. Therefore, several efforts have been made in the research community to further explore efficient control techniques for a reliable and stable DC microgrid. In spite of the numerous review papers published on DC microgrid control, so far, not any has given sufficient emphasis on the power flow analysis methods used in various DC microgrid topologies and the hybrid control topologies discussed in this review. In general, this paper presents a meticulous explanation of DC microgrid architecture; power flow analysis; control strategies with comparative analysis; challenges with recommendations; as well as classical and intelligent-based energy management strategy (EMS). Finally, suggestion for further research is presented. This review paper will go a long way in helping readers to understand the present state of development on DC microgrid control. [ABSTRACT FROM AUTHOR]

This paper examines the impact of green finance on environmental performance in developing countries. Using panel cointegration analysis and panel vector error correction model (VECM) to a sample of 76 developing economies from 2010 to 2019, this study confirms that carbon emissions (CO 2) is cointegrated with green finance, real gross domestic product, urbanization, and renewable energy under different specifications and therefore we estimate the long-run relationships among these variables. Specifically, both green finance and renewable energy are found to exert significant and inhibitory effects on CO 2 emissions, reaffirming the necessity to promote green finance and renewable energy. Results from the paper also document the existence of the Environmental Kuznets Curve and the increasing effects of urbanization on CO 2 emissions. Several policy implications and recommendations are drawn from this study. • We examine impact of green finance on environmental performance. • 76 developing economies from 2010 to 2019 are considered. • Green finance and renewable energy exert inhibitory effects on CO 2 emissions. • Results support the existence of the Environmental Kuznets Curve. [ABSTRACT FROM AUTHOR]

The primary purpose of this paper is to investigate the effects of two variables, trade openness and the issuance of green bonds, on the consumption of renewable energy in Southeast Asian countries. Quarterly data throughout 2016–2021 in the framework of the panel data method were used for the case of 6 selected countries (Indonesia, Malaysia, Philippines, Singapore, Thailand, and Vietnam). The results confirmed that the issuance of green bonds is an effective green financing tool in the implementation of the development policy of the deployment of renewable energy in the countries of the Southeast Asian region. The degree of trade openness has a driving effect on increasing renewable energy consumption due to the increased possibility of transferring green technologies and increasing interactions with leading countries in the field of sustainable development. The typical standard of green bonds, green scientific network (GSN), the development of e-commerce, and the publication of digital green papers are the recommended practical policies of this research. • Green bond is an effective tool to increase of deployment of renewable energy. • Trade liberalism increases the deployment of renewable energy. • Green R&D is a leading factor in the field of clean energy consumption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Renewable energy generation on energy security in G7 countries. • The panel ARDL, QQR, and Dumitrescu-Hurlin causality analyses were employed. • The impact of renewable energy generation on energy security was analyzed. Energy security has been brought into the foreground of political and economic agendas nowadays. However, this variable has been only in very few papers employed as dependent or independent variable. In most research so far, energy security is implied and is proxied by certain variables. The aim of this study is to investigate the relationship between energy generation from renewable energy sources and energy security in the G7 countries for the period 1980–2018 by using the panel autoregressive distributed lag, panel quantile-on-quantile regression and the Dumitrescu-Hurlin panel Granger causality analyses. The results reveal that there is a uni-directional causal link from renewable energy to energy security in the short-run and generating energy from renewable sources significantly reduces the risks that threaten energy security in the long run. Furthermore, quantile-on-quantile regression estimates indicate that, for the quantile above 0.5 in terms of renewable energy generation, energy security risks are reduced, and secure access to energy is strengthened in the G7 countries. The diverse implications generated by each methodology are particularly relevant today, given the current energy crisis in Europe and the pressing need to increase the share of renewable energy generation to mitigate energy security risks. [ABSTRACT FROM AUTHOR]

This paper investigates an innovative study on the performance of a hybrid condensing boiler-fuel cell micro-cogeneration system for single residential applications. It combines experimental and dynamic numerical investigations including renewable energy for green hydrogen production and solid storage. Basing on the hourly measurements for a typical winter day, a dynamic model was developed and validated against different home heating need. Highlighting the influence home energy needs on fuel cell operating mode, it shows that single homes with low energy demand led to reduce the fuel cell's yearly operation below 50 %. In low-energy homes, a reduction in fuel cell size led to an increase in yearly operation to 60-70 % and achieved a 55 % electrical coverage rate. The integration of metal hydride hydrogen solid storage, powered by renewable sources, is emphasized. This setup increases heat demand, influencing fuel cell operation. In winter season, fuel cell operated for an average of 611 h, compared to 61 h in summer. System efficiency averaged 91 % annually, peaked at 95 % in summer, and sustained 93 % when both FC and condensing boiler were switched on. [Display omitted] • Modeling of a hybrid Boiler-Fuel Cell MCHP system for residential energy management. • Calibration of the FC-MCHP model using experimental data from a real MCHP unit. • Electrical and thermal coverage of the FC-MCHP unit with green hydrogen production and storage under different scenarios. • Strategies for optimal hydrogen consumption in in residential application. • Impact of solid-state hydrogen storage on FC-MCHP consumption and thermal management. [ABSTRACT FROM AUTHOR]

This paper focuses on the design and use of a control system for a renewable energy production plant based on hydrogen. The proposed control system aims at ensuring the stability and smooth functionality of the plant, which consists of a (i) photovoltaic system connected to an electrolyzer through a battery, (ii) a DC/DC step down transformer, and (iii) an electrolyzer heat exchange system. In this study, solar irradiance is the main system input, and hydrogen production the main output. Since the system utilizes solar energy as input, it depends on the random input of solar irradiance, ambient temperature, and wind flow. Furthermore, the electrolyzer's functionality is subject to several operational variables including cell voltage, current, temperature, and pressure. The electrolyzer heat exchange system operates at specified water temperatures and flow rates. The DC/DC output voltage, and therefore the voltage supplied to the electrolyzer, is regulated by changing its duty cycle. To regulate hydrogen production in the renewable energy production plant, an efficient control system is required. Accordingly, in this work, a control system is designed accounting for three different electrolyzer technologies, alkaline, PEM (proton exchange membrane), and E-TAC (electrochemical - thermally activated chemical water splitting). Subsequently, the effectiveness of the control system is analyzed using Matlab and Simulink models. The main results indicate that the battery is a crucial element in the whole system as it supplies the necessary energy to the electrolyzer. By regulating the appropriate components, the proposed control system proved capable of minimizing power fluctuations and increasing system efficiency up to 20% depending on ambient conditions. Additionally, the results indicate E-TAC and PEM efficiencies 13% and 7% higher than alkaline, respectively. [Display omitted] • Design of a control system for three different electrolyzer technologies. • Use of control systems for electrolyzer voltage and heat exchange. • Photovoltaic system connected to an electrolytic one through a battery. • Proposed control system increases system efficiency up to 20%. [ABSTRACT FROM AUTHOR]

The development of sustainable energy sources has become a major challenge for society. Green hydrogen, produced through the electrolysis of water using renewable energy sources, offers a potential solution to reducing our dependence on fossil fuels. The paper examines the integration of green hydrogen into various sectors, such as transportation, industry, power generation, and heating, highlighting its potential to decarbonize traditionally carbon-intensive areas. Furthermore, it analyses the strategies and policies employed by the European Union, Australia, Japan, the United States, and Canada to drive the development and adoption of green hydrogen technologies. The challenges and barriers that need to be addressed to fully realize the potential of green hydrogen, such as technological limitations, infrastructure development, costs and economic feasibility, regulatory and policy frameworks, and public perception and acceptance, have been investigated. Recommendations for overcoming these challenges and accelerating the adoption of green hydrogen technologies are provided, and the importance of research and development in this sector is emphasized. • Green hydrogen offers a sustainable solution to reduce fossil fuel dependency, decarbonizing key sectors. • Analyzed policies from the EU, Australia, Japan, the US, and Canada to foster green hydrogen technologies. • Discussing challenges: green hydrogen potential, tech limits, infrastructure, costs, regs, and public views. • Emphasized the importance of R&D and offers accelerating the adoption of green hydrogen technologies. [ABSTRACT FROM AUTHOR]

In this paper, a novel stochastic risk-averse mixed-integer linear programming (MILP) model is developed for optimal electricity procurement of hydrogen fuel stations (HFSs) with responsive hydrogen demands. In the developed model, HFS operator may procure its required electricity through day-ahead (DA) market, bilateral contracts, a contract with withdrawal penalty (CWP) and balancing market. The HFS is committed to inject a pre-specified volume of hydrogen into a natural gas network. In the developed stochastic model, the uncertainties in hydrogen demand and DA market prices are characterized as random variables and modeled as scenarios. The developed model is a two-stage model in which the decisions on transactions with bilateral contracts are the first-stage decision variables and the other decision variables belong to the second stage. The risk of suffering from high procurement costs is modeled using the Conditional Value at Risk (CVaR). The results confirm the efficiency of the proposed model both in terms of reduction in HFS expected cost and risk alleviation. The results show that the transaction through bilateral contracts decreases the expected cost and CVaR respectively by 6% and 3%. The results also indicate that the participation in the balancing market decreases the expected cost and CVaR respectively by 6% and 1.6%. As per results, in scenarios in which DA market prices are lower than CWP prices, HFS operator prefers to pay a penalty fee and withdraw from CWP. The sensitivity of HFS profit to the weight factor of risk metric and the participation factor of responsive demands are assessed. [Display omitted] • A model is developed for electricity procurement of hydrogen fuel stations (HFSs). • The uncertainties in demands and market prices are considered. • HFS procures electricity by day-ahead and balancing market and bilateral contracts. • Impact of different markets and transactions on HFS profit is assessed. • Sensitivity of HFS profit to weight of risk metric is assessed. [ABSTRACT FROM AUTHOR]

Renewable energies are available as clean sources to replace fossil fuels. Providing continuous power without compromising the environment through hybridizing solar and biomass source is one of the promising solutions. This paper seeks to address thermodynamic, economic, and environmental analysis of a multi-generation system with the aim of supplying heating, cooling, electricity, fresh-water, and hydrogen. To do this, the considered system is divided into on-peak, mid-peak, and off-peak periods and modeled based on the consumption pattern at different hours of the day and night. Due to the availability of renewable energy during peak consumption periods, biomass, solar, and hybrid biomass-solar energies are used as energy sources. This leads to a reduction in biomass consumption and carbon dioxide emissions through storing approximately 10 tons of biomass during the day. A sensitivity analysis of the factors affecting the system's function indicated that a growth in solar radiation from 600 to 1000 W/m2, results in a 35% improvement in exergy efficiency, a 2.7% raise in the total cost rate, and a 32.4% drop in CO 2 emissions of the system. Moreover, by changing the biomass flow rate from 0.5 to 1.5 kg/s, the exergy efficiency and total cost rate improved by 9.28%, 1.3%, respectively, and the CO 2 emissions rate increased from 0.41 to 1.14 tons/MWh. In addition, focusing on addressing economic and environmental concerns, the optimization of the proposed hybrid system is performed in two categories of objective functions. In the second category optimization, exergy efficiency, fresh water production, total cost rate and CO 2 emissions are determined as 31.75%, 74.75 kg/s, 324.60 $/h and 3.55 tons/MWh, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Effective 3D anode was prepared by graphitization of corncob biomass at high temperature under an inert atmosphere. As an anode in the microbial fuel cells, the proposed electrode revealed very good performance in both batch and continuous modes when the process parameters were optimized. The physicochemical characterizations indicated that the surface of the prepared anode is decorated by micro porous layers array and composed of SiO 2 ‒incorporated graphite. Moreover, investigation the electrical properties showed very good electrical conductivity dependent on the preparation temperature; 6.9, 8.6 and 8.9 S/m for the electrode prepared at 900, 1000 and 1100 °C, respectively. The performance of the proposed anode was evaluated in air‒cathode single chamber microbial fuel cell driven by domestic wastewater without using exterior microorganisms. The electrochemical measurements, for the batch mode cell, displayed high power density generation upon utilizing the corncob electrode compared to commercial anodes; 100 ± 8, 135 ± 11 and 2010 ± 85 mW/m2 from cells assembled using carbon paper, carbon cloth and corncob‒1100 °C, respectively. Moreover, addition of sodium acetate strongly enhanced the cell performance as the generated power density was increased from 475 ± 30 to 1963 ± 90 mW/m2 after addition of the salt (5 g/l), however the experimental results indicated that 5 g/l is the optimum salt concentration. In a continuous mode cell, the results concluded that the proposed 3D anode can be used fresh or after colonization of a biofilm. Interestingly, the generated power from the continuous mode cell is higher than the batch mode system due to mass transfer resistance elimination. • Corncob has been successfully exploited as an effective anode in the microbial fuel cells. • The introduced anode has been utilized in batch and continuous mode cells. • The generated power density reached to be twenty folds compared to commercial electrodes. • The detected power density was further improved in continuous mode microbial fuel cells. [ABSTRACT FROM AUTHOR]

Sustainable energy demand drives innovation in energy production. Electrolysis of water can produce carbon-free hydrogen from renewable sources. This paper presents a bibliometric analysis of recent and highly referenced research on hydrogen electrolysers utilising the Scopus database to shed insight into future trends and applications. It has been discovered that the most frequently published type of study for top-ranked papers is the formulation of problems and simulations (38.3%), followed by a study of the state-of-the-art technology assessment (32.5%), laboratory research, design, and performance evaluation (24.2%), and reviews (5%). In general, 33.33% of articles focused on controlling hydrogen electrolyser efficiency. This study used different case studies from the global literature to conduct a complete evaluation of the electrolyser statistical analysis of the present state of the art, models or modes of operation, key challenges, outstanding issues, and future research. This evaluation will aid researchers in building a commercially successful hydrogen electrolyser. • A comprehensive review on hydrogen electrolyser is analysed for future research directions. • The problems, state-of-the-art technology, design, and performance evaluation is reviewed. • The control strategies are significantly boost the efficiency of hydrogen electrolysers. • A statistical analysis on electrolyser models, open issues, and future research trend is investigated. • This review will contribute to improve the efficiency and sustainability of electrolyser technology. [ABSTRACT FROM AUTHOR]

Hydrogen energy storage system (HESS) has excellent potential in high-proportion renewable energy systems due to its high energy density and seasonal storage characteristics. After detailing the volatility of wind speed, irradiance and load, this paper proposes a bi-level optimization model to analyze the economic operation of the wind-photovoltaic-hydrogen hybrid system (WPH-HS). First, the relationship between the source-load output matching and operating conditions of HESS is studied, two evaluation indicators are described, which can be adjusted by wind-solar complementarity on the source side and demand response on the load side. Second, considering the levelized cost of storage (LCOS), the total annual cost (TAC) calculation method of WPH-HS is presented, and this paper provides a new hybrid optimization technology of chaotic search, particle swarm optimization and non-dominated sorting genetic algorithm2. Finally, the system is simulated with the MATLAB software to determine the optimal sizing of components and minimize the LCOS while ensuring the optimal TAC. The simulation results are elaborated in detail. In particular, the added source-load interaction reduces the TAC and LCOS by 7.3% and 10.3%. When two indicators reach 0.03 and 0.1745, the system is economically viable with the LCOS of 0.276 USD/kWh. The hybrid optimization algorithm can achieve better result in fewer iterations. • The cross-season utilization of the hydrogen energy storage system is discussed. • A price bi-level model about the levelized cost of storage and the total annual cost is established. • Evaluation indicators are presented to promote the source-load interaction. • Effects of wind speed, irradiance, and loads are investigated for the levelized cost of storage. • A hybrid optimization algorithm based on three common algorithms is designed. [ABSTRACT FROM AUTHOR]

This paper has sorted out the general logic of the impact of COVID-19 on energy consumption. In the short term, the epidemic has forced governments to adopt different levels of lockdown measures. The total electricity consumption decreased and the share of renewable energy has increased. Based on the International Energy Agency's (IEA) data on electricity production and consumption, this paper analyzes the long-term effects: The COVID-19 pandemic does affect overall electricity demand and market structure in the short term, but in the long term, the impact of the pandemic is detrimental to the proportion of electricity generated from renewable sources. Increased, especially in hard-hit countries. The impact on countries with different levels of development is different, and countries with higher levels of economic development are better able to resist such exogenous shocks. The pandemic is still ongoing, how to steadily promote sustainable development? In this paper we suggest that to cope with climate change, to accomplish energy transformation and upgrading or even sustainable development, we should not only rely on reducing human activities, but give more support to countries with low development levels in realizing sustainable development. [ABSTRACT FROM AUTHOR]

In recent decades, the role of green energy in realizing green transition and addressing environmental degradation needs to be brought into full play. To promote green energy development in China, this paper examines the relationship among green economic growth, green finance, and green energy (3G) between 2011 and 2019. The heterogeneous, asymmetric, and mediation impact relationship that exists in the 3G nexus is also explored in this study. Accordingly, the results suggest that: (1) Green economic growth and green finance are positively associated with green energy, and the impact is heterogeneous on different types of green energy and in different regions; (2) the impact of green economic growth on green energy are asymmetric, while that of green finance is consistent; and (3) green innovative technology is an effective mediator between green economic growth and green energy, while the investment effect is not significant. This paper contributes to formulating several reasonable policies for improving the green energy industry and achieving sustainable development. It is essential to give full play to the transformation of green achievements to enhance the role of green economic growth in promoting the green energy industry. • This study explores 3G nexus (green economic growth, finance, and energy (GRE)) in China. • The heterogeneity, asymmetry, and mediating mechanism are further analyzed. • Green economic growth and green finance can significantly promote GRE. • The impacts of green economic growth and green finance on GRE are heterogeneous. • Green technological innovation is an effective mediator in the 3G nexus. [ABSTRACT FROM AUTHOR]

Given global warming, which limits the use of classical energy sources, renewables can provide a solution to the dilemma between environmental protection and sustainable economic growth. In this complex and changing context, green hydrogen can become a promising link between renewable energy sources and end users. However, although hydrogen has a high gravitational energy density, it has a very low volumetric energy density. This challenge requires hydrogen compression at several stages in the supply chain from electrolysis units to conversion, storage, and distribution. Recently, many studies have focused on hydrogen compression technologies. This paper provides an overview of recent advances in large-scale hydrogen compression. First, the role of hydrogen compression in providing clean energy for the future is explored. Then the thermodynamic concept of hydrogen compression is investigated. Gaining a proper understanding of compressor operating conditions in various operations in the large hydrogen industry is the next focus of this paper. Later, the capabilities and limitations of available mechanical compressors for the hydrogen industry, including reciprocation and centrifugal, are summarized. Finally, research gap and recommended new areas in this field are recognized. The presented insightful concepts provide students, experts, researchers, and decision-making working on large-scale hydrogen industry with the state of the art in hydrogen compressors industry. • Green hydrogen is a promising link between production and use of renewables. • Low molecular weight of hydrogen makes compression a crucial step in the green hydrogen chain. • Various operations in this industry need compressors with output pressures of 20 bar–200 bar. • Only reciprocating and centrifugal compressors can handle the required capacity in this industry. • Review of resources proves rapid progress in the design and reliability of hydrogen compressors. [ABSTRACT FROM AUTHOR]

Despite their economic success, the BRICS countries have yet to achieve environmental sustainability. On the other hand, these countries will not be able to maintain their economic expansion if they do not protect the natural environment. In this regard, this paper intends to assess the effects of financial integration (globalization) on ecological footprint. The paper also considers other ecological footprint drivers, including economic expansion, urbanization, renewable energy and technological innovation. The research utilizes a dataset spanning from 1990 to 2018. The study employed the method of moments quantile regression (MMQR) approach, which is robust to cross-sectional dependence and slope homogeneity issues. The outcomes from the MMQR disclose that the effect of financial globalization on ecological footprint is positive across all quantiles (0.1–0.90), thus validating the pollution haven hypothesis (PHH) in the BRICS nations. Furthermore, both renewable energy and technological innovation curb ecological footprint across all quantiles (0.1–0.90). Moreover, technological innovation is proven to impact the environment positively across all quantiles (0.1–0.90) via the path of urbanization. As a result, technological innovation is projected to help the BRICS nations achieve sustainable urbanization. The DOLS, FMOLS, FE-OLS outcomes also validate the outcomes of MMQR. Based on these results, policies were proposed. • MMQR applied to integrate asymmetric effects. • Renewable energy consumption and technological innovation derive ecological sustainability. • Financial integration-led Pollution-haven-hypothesis is confirmed. • Economic growth and urbanization lead to higher ecological footprints. • Technology innovation neutralizes the negative impact of urbanization on ecological sustainability. [ABSTRACT FROM AUTHOR]

This paper uses panel data on renewable energy in China. Thus, the current analysis fills the gaps by examining the relationship between green technology innovation and renewable energy and CO 2 emissions from 1990 to 2018. The current study examines all concerns connected to panel data analysis with advanced panel estimators, such as cross-sectional dependence, stationarity, variation in slope parameters, and structural break. Our findings show that test results reveal that green technology innovation and renewable energy have a negative and considerable influence on CO2 emissions in the long run. Moreover, the short-run relationship of green technology innovation, on the other hand, is not significant—as evidenced by the findings of robustness tests such as AMG and CCEMG. Other empirical results revealed that GTI, REN and NEN significantly reduced local CO 2 emission, while POP and PI had no obvious reduction effects on CO 2 emissions. Different GTIs had the same spatial "symbiotic effects" on CO 2 emission reduction in the short term, showing positive spatial spillover reduction effects. Lastly, we conclude that the use of green technology innovation has positive externalities. Some policies to assist green innovation technologies and renewable energy resources have been suggested for the Chinese government to enact. • This paper uses panel data on renewable energy in China. • The current study examines all concerns connected to panel data analysis with advanced panel estimators. • The short-run relationship of green technology innovation is not significant. • We conclude that the use of green technology innovation has positive externalities. [ABSTRACT FROM AUTHOR]

• Impacts of export quality on economic progress are examined. • The role of economic complexity for economic growth is investigated. • 28 OECD country's data is utilized from 1990 to 2019. • Export quality and economic complexity induce sustainable growth. • Institutional quality is a significant determinant for economic growth. It is important to unearth the role of structural change factors for sustainable growth in developed economies. Economic complexity, export product quality, and institutional indicators represent the overall structural change and transformation in an economy. This paper probed the influence of export product quality and economics of complexity on economic growth for 28 OECD (Organization for Economic Co-operation and Development) countries using the data from 1990 to 2019. In doing so, the study employs three-panel data econometric models to investigate the role of economic complexity, export quality, and institutional quality on economic development. The paper performs the empirical tests, including the cross-sectional related dependency methods and cointegration techniques. As per the results emerging from fully modified OLS (FMOLS) and dynamic OLS (DOLS) estimation, export quality and financial development positively and significantly strongly impact growth in the long run. The empirical conclusions report detailed discussion on sustainable growth and discuss novel implications concerning product quality and institutional performance. The conclusions stress the practical implications for sustainable economic growth of OECD economies. [ABSTRACT FROM AUTHOR]

• Straight-forward, in-expensive birchwood hydrolysis. • Low requirement of reagents. • Increased rate of biogas production. The global demand for non-fossil energy sources is increasing rapidly. As a result, biogas presents a suitable alternative; however, first generation biofuels (e.g., sugar cane) potentially impact food crops globally. Second generation biofuels based on lignocellulose-based biomass are being used more frequently as they do not impact food crops. Furthermore, in Northern Europe, there is a significant interest in utilizing birchwood and paper mill waste for biogas production due to its high availability. The utilization of birchwood for biogas has significantly improved in recent years with the improvement of required pretreatment processes. To date, the most effective and economically feasible pretreatment in an industrial context is the steam explosion of lignocellulose-based biomass. Despite this, there is potential for releasing more digestible components from this biomass by efficiently degrading the lignocellulose components. This research presents another pretreatment that can be applied to steam-exploded wood based on ultrasonication and Fenton reagents. It was observed that by treating the steam exploded birchwood with ultrasonication and mild concentrations of Fenton reagents, an increase in the rate of biogas production was achievable. This would allow the increase in biogas yield of a continuously feed industrial anaerobic digester without increasing the size of the reactor. [ABSTRACT FROM AUTHOR]

Modern electricity networks may face inertia shortages based on increasing inverter-based renewable energy penetration, along with the (often concurrent) decommissioning of aging synchronous thermal generators. In the South African network, the market share of coal generation is projected to decrease significantly based on the country's energy policy, primarily to be replaced by wind and solar PV. In this paper the inertia adequacy on the future South African network is evaluated, and the viability of converting retired synchronous generators to synchronous condensers is assessed based on sufficiency of inertia support provided and economic viability. It is found that by 2030, the South African network will have insufficient inertia for a significant portion of the year. However, significant improvements in Rate of Change of Frequency and frequency nadir are observed when incorporating inertia from converted synchronous condensers during multiple-contingency trip events. Finally, the conversion of synchronous generators to synchronous condensers is found to be the least-cost solution when compared to the installation of new synchronous condensers or of large-scale battery systems. The contributions made in this paper highlight the importance of considering network inertia in establishing a national energy policy, while also informing solutions to future inertia constraints. • The future South African electricity network will face significant inertial shortages by 2030. • Converting retired synchronous generators to synchronous condensers will significantly reduce inertia shortages. • The conversion of retired synchronous generators to synchronous condensers is cost-effective as an inertia support mechanism [ABSTRACT FROM AUTHOR]

This study aims to investigate the factors of renewable energy consumption in the fifth Technology Revolution with specific evidence from ASEAN countries. The study applies an autoregressive distributed lag (ARDL) approach. The paper also uses the unrestricted fixed and random panel data methods. The manuscript identifies significant factors such as technological innovation, governmental policies, public awareness, electricity consumption, country population, foreign direct investment inflows, imports, exports, and economic growth that have influenced the renewable energy sector in these nations. This study also investigates the determinants that influence renewable energy in the context of international integration and the fifth technology revolution in ASEAN countries. The research analyzes data spanning two decades, from 2000 to 2022, through a combination of econometric modeling and machine learning techniques. Preliminary findings indicate that technological innovation, government policies, and public awareness significantly affect renewable energy consumption in these countries. The empirical results offer insights for policymakers and stakeholders in leveraging technological advancements for sustainable energy development. The findings from this study on the determinants of renewable consumption in the context of the Fifth Technology Revolution in ASEAN countries also have several important policy implications for the sustainable development goal. • This study aims to investigate the factors of renewable energy consumption in the fifth Technology Revolution. • The study uses panel data analysis, and the paper identifies significant factors that have influenced the renewable energy sector. [ABSTRACT FROM AUTHOR]

The crux to meet the daily exponential growth in power demand and reduce the carbon footprint has seen to rejuvenate the consideration of large-scale renewable energy penetration (LsREP) in the power grid. Conversely, the emergence of the LsREP in the power grid is linked to frequency instability due to the mismatch between the conventional-based synchronous generator and inverter-based generator. Furthermore, the drastic drop in the kinetic energy storage due to the minimal rotating mass resulted in low inertia. This study presents a detailed work evaluating the effectiveness of different low-inertia power grid control techniques such as adaptive, predictive, virtual, and conventional controls. Furthermore, the study revealed gaps in this research area and thus, recommends multi-objective optimization control strategies to accommodate extant grid's dynamism for a better representation and control of low-inertia grid in the presence of perturbations. In addition, the bibliometric analysis was optimized through the VOSviewer -bibliographic software. The analyzed data were extracted from the Scopus database for the period of 2013 to mid-2023 covering 1267 related documents from conference papers, conference reviews, articles, and reviews on low-inertia grid control strategies. The results from the analysis revealed six (6) clusters of new research areas based on the co-occurrence keywords from the assessed papers. • The study classified the low-inertia grid control into 4 categories viz. Adaptive, Predictive, Virtual, and Conventional. • The strengths and limitations of each control classification in the presence of load perturbations were well discussed. • The bibliometric analysis via the VOSviewer revealed top countries with scholarly publications on low-inertia grid control. • The research recommends multi-objective dynamic control strategies for a better control of low-inertia power grids. [ABSTRACT FROM AUTHOR]

Currently, the research agenda of energy transition is gaining momentum. This paper conducts a comprehensive review of this body of research by presenting a framework that describes the connotations, mechanisms, and effects of energy transitions. The study concludes that the energy transition will lead to the reconstruction of energy system elements beyond the energy sector, with the dual connotations of explicit transition and implicit transition. The explicit transition is usually captured by statistic data and information, for instance, energy utilization type, structure, form, transportation mode, and spatial pattern. The implicit transition involves shifts in energy security, geopolitical structure, energy power, energy justice, and energy governance, which receives relatively less attention in current literature. The energy transition is a highly socialized process, driven by many intertwined factors such as technological innovation, market mechanisms, policy arrangements, and sociocultural factors, triggering profound socio-economic and ecological effects. Looking ahead, it is urgent to pay attention to the multi-scale effects of energy transition, avoid the risks brought by energy transition, and ultimately achieve just energy transition. This paper provides a novel perspective and contributes to the literature on theoretical understanding and advancement of energy transition. • This paper proposes an analytical framework to enrich energy transition research. • Energy transition has dual connotations of explicit transition and implicit transition. • Energy transition is a highly socialized process driven by a multitude of factors. • Energy transition brings profound socio-economic and ecological effects. [ABSTRACT FROM AUTHOR]

Urban energy supply includes more renewable energy, but renewable energy, such as wind and photovoltaic, is intermittent and connected to the grid and impacts the safe operation of the power system. For urban multi-type energy dispatching, this paper proposed a day-ahead multi-energy robust optimization dispatching method for an urban power grid with a high proportion of renewable power. Firstly, the power supply and load operation scenarios of the urban energy supply system are constructed. Multiple typical scenarios are formed based on fully considering the uncertainties caused by renewable energy and load prediction. A robust optimal scheduling model with system constraints was constructed based on the tuning capacity of adjustable generator sets and energy storage devices in the power grid, with multi-system functional cost optimization as the objective function. Extending the augmented Lagrange multiplier Method, the Alternating Direction Method of Multipliers (ADMM) is proposed to solve the constructed model. The effectiveness of the proposed method is verified by some examples based on the data of an actual power grid in China. [ABSTRACT FROM AUTHOR]

Green steel, produced using renewable energy and hydrogen, presents a promising avenue to decarbonize steel manufacturing and expand the hydrogen industry. Australia, endowed with abundant renewable resources and iron ore deposits, is ideally placed to support this global effort. This paper's two-step analytical approach offers the first comprehensive assessment of Australia's potential to develop green steel as a value-added export commodity. The Economic Fairways modelling reveals a strong alignment between prospective hydrogen hubs and current and future iron ore operations, enabling shared infrastructure development and first-mover advantages. By employing a site-based system optimization that integrates both wind and solar power sources, the cost of producing green steel could decrease significantly to around AU$900 per tonne by 2030 and AU$750 per tonne by 2050. Moreover, replacing 1% of global steel production would require 35 GW of well-optimized wind and solar photovoltaics, 11 GW of hydrogen electrolysers, and 1000 square kilometres of land. Sensitivity analysis further indicates that iron ore prices would exert a long-term influence on green steel prices. Overall, this study highlights the opportunities and challenges facing the Australian iron ore industry in contributing to the decarbonization of the global steel sector, underscoring the crucial role of government support in driving the growth and development of the green steel industry. [Display omitted] • Australia could produce low-cost green steel for value-added export • Strong correlation between hydrogen hubs and iron ore operations • Existing infrastructure supports the roll-out of the industry • Optimized generation mix reduces storage, curtailment and production costs • Iron ore prices substantially influence green steel prices in the long term [ABSTRACT FROM AUTHOR]

Power-to-ammonia (P2A) technology has attracted more and more attention since ammonia is recognized as a natural zero-carbon fuel. In this context, this paper constructs a renewable energy powered multi-energy hub (MEH) system which integrates with a thermo-electrochemical effect based P2A facility. Subsequently, the energy management of proposed MEH system is casted to a multi-agent coordinated optimization problem, which aims to minimize operating cost and carbon dioxide emissions while satisfying constraints. Then, a novel multi-agent deep reinforcement learning method called CommNet is applied to solve this problem to obtain the optimal coordinated energy management strategy of each energy hub by achieving the distributed computation of global information. Finally, the simulation results show that the proposed method can achieve better performance on reducing operating cost and carbon emissions than other benchmark methods. [ABSTRACT FROM AUTHOR]

• We employed MRA to specify the authentic empirical effect based on 328 estimation results from 33 primary studies. • Financial development leads to higher renewable energy consumption / use / capacity / production according to the MRA. • There is no publication bias in the existing literature. • The authentic empirical effect may change depending on financial development or renewable energy indicators used, time period covered, the unit analyzed, and the estimation technique employed. • There is an omitted variable bias in the existing literature. The current paper tries to determine and quantify the authentic empirical effect of financial development on renewable energy beyond publication selection bias, if any, based on 328 estimation results from 33 primary studies that were published or presented over the period of 2009-2022. Bivariate and multivariate FAT-PET analyses were used as tools of meta-regression analysis. A positive significant authentic empirical effect of financial development on renewable energy is found as a first contribution. Hence the results support Hypothesis 1; by offering more reliable, efficient, and less costly funds to investors; whether private or public, financial development boosts renewable energy. An absence of publication bias is resulted regarding the overall findings of the primary studies or design characteristics (moderating variables) as a second contribution. Based on the results for moderating variables, the authentic empirical effect may change in direction and magnitude due to the financial development or renewable energy indicators used, the time period covered, the unit analyzed, and/or the estimation technique employed as a third contribution. Omitted variable bias is found in the existing literature analyzing this subject. [ABSTRACT FROM AUTHOR]

Renewable energy adaptation can play a critical role to halt climate change, although many researchers in the past tried to estimate its effect toward the environment, but the findings are still unclear and complex due to limitation of data and adopted methodologies. Therefore, to overcome the weaknesses, this paper aims to re-investigate the role of renewable energy adaptation, financial development and globalization toward environmental quality and economic progress in leading economies, we call it big five economies (B5) of the world. These economies (USA, China, UK, Germany, and Japan) were chosen based on ranking by the IMF. In this paper, we applied panel techniques for data analysis including panel data unit roots test, padroni cointegration analysis and panel data FMOLS and panel DOLS. Further, to explore country specific results and to ensure the robustness of findings, frequency domain causality test was applied. Results of estimation reveal that renewable energy adaptation mitigate the environmental impact to improve environmental quality and reinforce economic progress in B5 countries. Although, financial development, capital formation, natural resources and globalization improve economic progress, but these factors create adverse consequence for the environmental quality. Similarly, it can be stated that it's a tradeoff between economy and the environment. Further, the role of trade is found as constructive for environmental quality and economic progress in B5 economies. We believe that the conclusions of our study hold promise for key insights for the policy development. • This paper adopted panel of Big five economies. • Renewable energy adaptation holds a critical role for the environment. • Financial development in selected economies boost the economic output. • Resources utilization reinforce economic progress and environmental degradation. [ABSTRACT FROM AUTHOR]